Decalcomania paper



July 9,1935 J. LAURlN- DECALCOMANIA PAPER Filed Fb. 11, 1955 I Patented July 9, 1935 UNITEDJSTATE PATENT orrlc-E Q1 $2,007, 04} j f I f I EC WO Q f [Y mt"..-taatta wsama. i 7 eett i tr jmm 11, 1933. sens n 656,311

Y Q2 em r er141+3e A decalcomania paper manufactured'by m'ethods typical of those heretofore used commercially comprises a fairlysubstantial sheet-of backing paper coated on one si'de with aniadhesive that 6 is adapted to take printing ink. The composition of the adhesive'coating variesf somewhat with the preferences of different manufacturersand also with the requirements of .the printers. 1' In some cases thecoating is made. up of layers 1m ing difierent characteristics, that. next to the backing sheet usually being more readily soluble in water than the other layer or layers so that it can more easily be separated from the backing sheet. Sometimes, also, the adhesive layer in- .5 eludes other constituents such asmetal powders, pigments, or the like, designed to make the coating substantially opaque, and in some cases a thin film of some water insoluble material, such as a' lacquer, is applied to the outer surface of the ad- !0 hesive coating and is designed to take the printingink.

' In printing the decalcomania design on such paper it is customary. to apply the printing ink in a fairly thick body and frequently it'is necessary to repeat the printing operation one or more times in order to build up an ink body of the desired thickness. Because the ink is applied. heavily there is a very serious tendency for the ink from the printed surface of one sheet to transfer or offset on the back of the next adjacent sheet, and in order to prevent this action it is customary to interpose a sheet of waxed paper or of some other thin paper of suitable character between the adjacent printed sheets as they are stacked up at the delivery end of the printing machine. These slip sheets or interleaved sheets are left in place until after the ink has dried. I

It is obvious that the necessity for inserting these slip sheets increases theexpense'of producing the printed decalcomanias. The present invention is especially concerned with the problem presented by these conditions, and it aims so to improve decalcomania papers and the meth- 5 ods of making them as to avoid the necessity for slip sheeting.

The nature of the invention will be readily.

understood from the following descriptionlwhen read in connection with the accompanying drawing, and the novel features will be particularly pointed out in the appended claims.

In the drawing, v Figure 1 is a perspective view of a decalcomania paper made in accordance with this invention; and V scale of the sheet shown in Fig. 1.

Fig.2 is 'a vertical, sectional view on a large jThe decalco' 'ia sheet shown in the drawing comprises a backing sheet '2 which usually con-- sistsof a fairlyheavy sheet of paper containing 5 relativelylittle sizing so that it will readilyabsorb the water used in separating thebacking sheet from the decalcomania design durin the application o'fsaid design to theworkn Qnej face of the sheet 2 carries'a coating 3 of adhesive, .the surface of which is adapted to take decalcomania printing. This coating may be of any suitable nature, such, for example, as any of those commonly used commercially. It should be united to the backing sheet by a union which can readily be dissolved in water or easily broken so that the backing sheet can conveniently be stripped from the coating when necessary. In a typical case the inner layer of adhesive consists of a mixture of starch and dextrine. So far as these features are involved the prior practice may be followed since the present invention is not espe-. cially concerned with them.

For the purposes of this invention the rear surface of the backing sheet is roughened by spraying particles of some material upon it that will stick to the paper but which preferably do not have any great. degree of adhesion for the printing ink. A preparation suitable for this purpose may consist of some filler such as chalk, talc, or

the like, dispersed in a solution of some inexpensive gum, such as dextrine or starch, or the filler may be omitted and a solution of such a gum may be sprayed on the paper. This spray should not be in a very finely divided form or mist, but 5 should consist of small globules which will be well. scattered over the rear surface of the backing sheet so as to form small lumps or excres- 'ences, as indicated at 4, which may vary considerably in size. and will be-irregularly spaced, but 40 will be distributed over substantially the entire rear surface of the sheet. These lumps or small particles ofmaterial dry relatively quickly. The spraying operation may be performed in conjunction with that of applying the adhesive coating to the opposite face of the sheet so that it will add relatively little to the expense of manufacture of this product.

This method produces a decalcomania sheet in which the lumps or excresences on the back of 5 the sheet engage the printed face ofthe next adjacent sheet as the sheets are stacked upon issuing from the printing machine, and such lumps or projections serve to hold the printed 5 race of the sheet spaced fromthe main body 0f the backing sheet. In other words, the small particles attached to the back of the sheet provide a multiplicity of points of contact with the printed face of the next adjacent sheet which are so small and so distributed that no substantial transfer of, ink from the printed face of one sheet to the back of the next adjacent sheet occurs. By using a gum which does not readily adhere to the printing ink, any loss of ink from the printed surface can be practically eliminated.

In addition to roughening the back of the sheet in the manner above described, it is also preferable to use an ink dryer in the surface coating of gum to which the printing ink will be applied, as has beenproposed heretofore, so as to make the ink dry as rapidly as possible. It has been demonstrated in actual practice that paper manufactured in accordance withthis invention can be printed by substantially the methods heretofore commonly used in printing decalcomanias without the use of slip sheets. Since the lumps or projections at the back of the sheet are themselves water absorbent and are present'in small bodies, they do not materially reduce the absorption of water by the backing sheet during the process of separating this sheet from the printed surface in completing the transfer.

While I have herein shown and described a preferred embodiment of my invention, it will be evident that the invention may be embodied in other forms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

1. A decalcomania paper comprising a backing sheet of water absorbent paper carrying a coating on one face thereof adapted to take decalcomania printing and bonded to said sheet by a water soluble adhesive. said coated surface of the paper being smooth, and the opposite side of said sheet having a multitude of small lumps adhesively bonded thereto and forming raised portions serving to hold the inked surface of a superposed sheet away from the main body of said backing sheet, said lumps including a water soluble bonding agent.

2. A decalcomania paper comprising a backing sheet of water absorbent paper carrying a coating on one face thereof adapted to take decalcomania printing, said coated surface of the paper being smooth, the opposite side of said sheet having a surface characterized by the presence of a multiplicity of small lumps of water absorbent material adhesively bonded to said surface and serving to hold the inked surface of a superposed sheet away from the main body of said backing sheet.

JOHN MACLAURIN. 

